# Another aspect of magnetic poles shifting **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [January 13, 2007, 8:55am UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821 "2007-01-13T08:55:13Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![dougie\_monty](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dougie\_monty](https://boards.straightdope.com/u/dougie_monty)\ **Post date:** [January 13, 2007, 8:55am UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821/1 "2007-01-13T08:55:13Z")
The article on shifting magnetic poles didn’t answer two questions of mine, one of which was discussed to some extent years ago: 1. Would the shifting magnetic poles cause the Van Allen radiation belts to collapse, covering the earth with deadly fallout? 2. Would such movement of the magnetic poles cause the earth’s _rotational axis_ to shift? :eek: ---
**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\ **Post date:** [January 13, 2007, 11:28am UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821/2 "2007-01-13T11:28:36Z")
[Link to Cecil’s article.](http://www.straightdope.com/columns/070112.html) ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [January 13, 2007, 12:10pm UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821/3 "2007-01-13T12:10:13Z")
This one will probably make more sense if we move it to CoCC. **samclem** GQ moderator ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [January 13, 2007, 5:05pm UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821/4 "2007-01-13T17:05:49Z")
[QUOTE=dougie\_monty] The article on shifting magnetic poles didn’t answer two questions of mine, one of which was discussed to some extent years ago: 1. Would the shifting magnetic poles cause the Van Allen radiation belts to collapse, covering the earth with deadly fallout? 2. Would such movement of the magnetic poles cause the earth’s _rotational axis_ to shift? :eek: [/QUOTE] 3. I’m not an expert here, but I don’t think so. It’s not like the VA belts are a bunch of radiation held up against gravity and it’ll fall if the magnetic fields weren’t there. It’s more like the magnetic field makes regions where charged particles get stuck as they fly past the Earth. If the magnetic field drops they’ll just fly off into space like they would have if they hadn’t gotten trapped in the first place. 4. I’m pretty sure the answer is no. There’s not very much angular momentum in the field itself, so changes in the field could only have a very tiny effect on the _huge_ angular momentum of the Earth’s rotation. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 13, 2007, 5:31pm UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821/5 "2007-01-13T17:31:55Z")
Considering that we have a great deal of evidence for past pole shifts, occurring about 60 times in the last 20 million years or so, it seems likely that the answer to both questions is no. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [January 13, 2007, 9:28pm UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821/6 "2007-01-13T21:28:06Z")
[QUOTE=dougie\_monty] The article on shifting magnetic poles didn’t answer two questions of mine, one of which was discussed to some extent years ago: 1. Would the shifting magnetic poles cause the Van Allen radiation belts to collapse, covering the earth with deadly fallout? 2. Would such movement of the magnetic poles cause the earth’s _rotational axis_ to shift? :eek: [/QUOTE] [ol][li]Yes, without a magnetic field the Van Allen belts would collapse, or at least become much weaker. Would this “[cover] the earth with deadly fallout”? No, only nuclear weapons or other impact events cause [fallout](http://en.wikipedia.org/wiki/Nuclear_fallout). It would result in a greater amount of solar radiation reaching the atmosphere and possibly the Earth’s surface, resulting in the effects as described by Cecil. So what? The effects on chronic health and the ecosystem would be measureable, but not in and of themselves extinction threatening (though resultant climatological effects might be significant and dramatic). As Cecil notes, the effects will occur over an anticipated span of thousands of years…longer than civilization has existed on the planet so far. Cecil’s right: we’ll deal.[/li][li]The amount of energy stored in the Earth’s magnetic field isn’t even a rounding error compared to the angular momentum from the Earth’s rotation. You might be able to measure it with sophisticated instrumentation, but save for the impact on orbital and celestical mechanics calculations, the effect would be insignificant.[/ol][/li]Stranger ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [January 15, 2007, 6:01pm UTC](https://boards.straightdope.com/t/another-aspect-of-magnetic-poles-shifting/387821/7 "2007-01-15T18:01:39Z")
The flipping of the Earth’s magnetic field is really only talking about the dipole moment. What about higher moments? How strong are the higher moments? Will energy be transferred from the dipole field to the quadropole field as the dipole field fades? For a wild guess, I’d think that the overall strength of the Earth’s magnetic field will remain about the same, only reorganizing into higher moments until the dipole is completely switched.